This invention relates generally to seeding implements such as grain drills, and more specifically, to press wheel structure for such implements.
Press wheel types of grain drills utilize gangs of press wheels mounted in trailing relationship to furrow openers for firming the soil over seed to assure good soil-seed contact. To help provide better and more uniform firming action over slightly irregular field surfaces, some grain drills such as the John Deere 9000 series Press Wheel Grain Drill utilize pivoting gangs of press wheels. Each gang is pivotally connected to the implement frame by a fore-and-aft extending pivot located above the gang. Although the pivotal connection permits each gang to work relatively independently over contours and to pack the soil more uniformly than a fixed press wheel gang assembly, it does not permit the press wheels located directly under the pivot to move vertically with respect to the frame. When these press wheels closely adjacent the pivot encounter an obstruction, the entire implement frame may be lifted and supported on one or two of the press wheels. This severely stresses the press wheels and allows the machine to be raised out of the ground, interrupting seed placement. Therefore, although the present pivot arrangement works well for small obstructions and slight ground nonuniformities, larger obstructions, particularly when encountered near the pivot location, can adversely affect the planting characteristics of the drill.